The present invention relates generally to gas turbine engines, and, more specifically, to expansion joints therein for accommodating differential thermal movement of fluid carrying components.
A gas turbine engine includes a compressor for compressing air which is suitably mixed with fuel and ignited in a combustor for generating hot combustion gases which flow downstream through one or more turbines. Various components of the turbines are cooled by using a portion of the compressed air bled from the compressor for use as cooling air. The cooling air bled from the compressor is channeled through suitable conduits and joints to the various components requiring cooling, with many of the conduits being subjected to differential thermal movement and vibratory excitation during operation.
Fluid carrying joints such as those used in the bleed air system take various conventional forms including ball and socket joints which allow relative pivotal movement, with the joints also being conventionally configured for also accommodating differential translation between adjacent ends of the conduits. However, traditional graphite ball joints are subject to undesirable leakage in view of the various differential pivotal and translation movement to which the joint is subjected to during operation, as well as due to vibratory excitation. As the ball joints wear during operation, leakage therefrom becomes more and more of a problem until the traditional graphite ball joints require replacement at substantial cost.